assertNever no longer crashes on string input (microsoft#29764)

sandersn · web-flow · commit 33af4ea250ec · 2019-02-06T08:57:24.000-08:00
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
@@ -1652,7 +1652,7 @@ namespace ts {
         }
 
         export function assertNever(member: never, message = "Illegal value:", stackCrawlMark?: AnyFunction): never {
-            const detail = "kind" in member && "pos" in member ? "SyntaxKind: " + showSyntaxKind(member as Node) : JSON.stringify(member);
+            const detail = typeof member === "object" && "kind" in member && "pos" in member ? "SyntaxKind: " + showSyntaxKind(member as Node) : JSON.stringify(member);
             return fail(`${message} ${detail}`, stackCrawlMark || assertNever);
         }
 
diff --git a/src/testRunner/unittests/asserts.ts b/src/testRunner/unittests/asserts.ts
@@ -5,5 +5,8 @@ namespace ts {
             assert.throws(() => assert.deepEqual(createNodeArray([], /*hasTrailingComma*/ true), createNodeArray([], /*hasTrailingComma*/ false)));
             assert.deepEqual(createNodeArray([createIdentifier("A")], /*hasTrailingComma*/ true), createNodeArray([createIdentifier("A")], /*hasTrailingComma*/ true));
         });
+        it("assertNever on string has correct error", () => {
+            assert.throws(() => Debug.assertNever("hi" as never), "Debug Failure. Illegal value: \"hi\"");
+        });
     });
 }

Original file line number	Diff line number	Diff line change
`@@ -1652,7 +1652,7 @@ namespace ts {`
`1652`	`1652`	`}`
`1653`	`1653`
`1654`	`1654`	`export function assertNever(member: never, message = "Illegal value:", stackCrawlMark?: AnyFunction): never {`
`1655`		`- const detail = "kind" in member && "pos" in member ? "SyntaxKind: " + showSyntaxKind(member as Node) : JSON.stringify(member);`
	`1655`	`+ const detail = typeof member === "object" && "kind" in member && "pos" in member ? "SyntaxKind: " + showSyntaxKind(member as Node) : JSON.stringify(member);`
`1656`	`1656`	return fail(`${message} ${detail}`, stackCrawlMark \|\| assertNever);
`1657`	`1657`	`}`
`1658`	`1658`
Original file line number	Diff line number	Diff line change
`@@ -5,5 +5,8 @@ namespace ts {`
`5`	`5`	`assert.throws(() => assert.deepEqual(createNodeArray([], /hasTrailingComma/ true), createNodeArray([], /hasTrailingComma/ false)));`
`6`	`6`	`assert.deepEqual(createNodeArray([createIdentifier("A")], /hasTrailingComma/ true), createNodeArray([createIdentifier("A")], /hasTrailingComma/ true));`
`7`	`7`	`});`
	`8`	`+ it("assertNever on string has correct error", () => {`
	`9`	`+ assert.throws(() => Debug.assertNever("hi" as never), "Debug Failure. Illegal value: \"hi\"");`
	`10`	`+ });`
`8`	`11`	`});`
`9`	`12`	`}`